Adult neurogenesis regulates social dominance and anxiety

In mice, social dominance has been associated with anxiety trait and reduced stress resilience. However, the underlying mechanisms of this association remain unknown. Here, we tested the hypothesis that adult hippocampal neurogenesis may underlie dominance behaviour and anxiety.First, our observations in group-housed males unveiled that dominant mice exhibited heightened trait anxiety and vulnerability to stress when compared to their subordinate counterparts. Furthermore, we observed a reduction in hippocampal neurogenesis specifically within the ventral hippocampus of stressed dominant mice. In addition, dominant mice displayed reduced neurogenesis in the dorsal DG as compared to subordinates under baseline conditions. Then, we tested the role of adult neurogenesis in the regulation of dominance behaviour by experimentally ablating neurogenesis. Our results revealed that diminishing neurogenesis before the establishment of a social hierarchy in group-housed males heightened the probability of mice adopting a dominant status in a social confrontation tube test. Simultaneously, this reduction in neurogenesis correlated with an increase in anxiety levels. Finally, when neurogenesis was impaired, socially isolated mice exhibited an increased innate dominance behaviour towards strangers (i.e., situational). Together, these results indicate that adult neurogenesis regulates hierarchical and situational dominance behaviour along with anxiety-related behaviour. These findings lay the groundwork for investigating the establishment of social hierarchy and the disruption of dominance behaviour in psychiatric conditions associated with anxiety.